Nanae Yamano, the Thunder fan artist from the Tokyo suburbs, went to her first NBA game. She was treated like a celebrity.

Nanae Yamano, an Oklahoma City Thunder superfan who happens to be a stay-at-home mother in the Tokyo suburbs, had never been to an NBA game before this week. She had never been to Oklahoma City. She had never been anywhere outside Japan.

She didn’t know how she would handle watching her favorite team in person—an idea so far...